A chromium-free passivation agent and processing technology

Through differentiated treatment and multi-step sealing process, a dense chromium-free passivation film is formed, which solves the problems of uneven film formation and poor adhesion of chromium-free passivation process on power transmission towers, and achieves high-efficiency anti-corrosion performance, making it suitable for long-term anti-corrosion and large-scale production of power transmission towers.

CN122303870APending Publication Date: 2026-06-30YUNNAN DONGDIAN LINE MATERIAL
View PDF 0 Cites 0 Cited by

Patent Information

Authority / Receiving Office
CN Β· China
Patent Type
Applications(China)
Current Assignee / Owner
YUNNAN DONGDIAN LINE MATERIAL
Filing Date
2026-04-15
Publication Date
2026-06-30

AI Technical Summary

Technical Problem

Existing chromium-free passivation processes suffer from uneven film formation, poor adhesion, and insufficient corrosion resistance in power transmission tower applications, making it difficult to meet the demands of high standards and large-scale production.

Method used

A dense, chromium-free passivation film is formed by employing differentiated electrolytic degreasing and surface micro-activation treatment, combined with low-frequency ultrasonic-assisted impregnation, gradient temperature curing, and secondary film-forming and sealing treatment with phytic acid-based sealing liquid.

Benefits of technology

A chromium-free passivation film with a smooth and dense surface, excellent adhesion, and outstanding resistance to salt spray corrosion was obtained, which comprehensively surpasses the traditional hexavalent chromate passivation film and meets the needs of long-term corrosion protection and large-scale production of power transmission towers.

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN122303870A_ABST
    Figure CN122303870A_ABST
Patent Text Reader

Abstract

This invention relates to the field of passivation treatment technology, specifically to a chromium-free passivation agent and treatment process. The method includes: classifying power transmission tower workpieces that have undergone hot-dip galvanizing and cooling to room temperature; performing differentiated electrolytic degreasing and surface micro-activation treatments according to the classification results; rinsing with deionized water and drying; completely immersing the pre-treated workpieces in the chromium-free passivation agent and applying low-frequency ultrasonic-assisted impregnation film formation; sending the pre-dried workpieces into a hot air circulating oven for gradient temperature curing with simultaneous segmented humidity control; immersing the cured workpieces in a phytic acid-based sealing solution for a secondary film formation and sealing treatment; removing them and drying them with constant hot air at 60-80Β°C; and naturally cooling the sealed workpieces to room temperature to complete the chromium-free passivation treatment. This achieves chromium-free and environmentally friendly passivation, suitable for various components of power transmission towers, and significantly improves the corrosion resistance of the galvanized layer.
Need to check novelty before this filing date? Find Prior Art